Premature cardiovascular events and mortality in south Asians with type 2 diabetes in the United Kingdom Asian Diabetes Study – effect of ethnicity on risk

Abstract

Background/Aim:

People of south Asian origin have an excessive risk of morbidity and mortality from cardiovascular disease. We examined the effect of ethnicity on known risk factors and analysed the risk of cardiovascular events and mortality in UK south Asian and white Europeans patients with type 2 diabetes over a 2 year period.

Methods:

A total of 1486 south Asian (SA) and 492 white European (WE) subjects with type 2 diabetes were recruited from 25 general practices in Coventry and Birmingham, UK. Baseline data included clinical history, anthropometry and measurements of traditional risk factors – blood pressure, total cholesterol, HbA1c. Multiple linear regression models were used to examine ethnicity differences in individual risk factors. Ten-year cardiovascular risk was estimated using the Framingham and UKPDS equations. All subjects were followed up for 2 years. Cardiovascular events (CVD) and mortality between the two groups were compared.

Trial registration number:

ISRCTN 38297969.

Findings:

Significant differences were noted in risk profiles between both groups. After adjustment for clustering and confounding a significant ethnicity effect remained only for higher HbA1c (0.50 [0.22 to 0.77]; P = 0.0004) and lower HDL (−0.09 [−0.17 to −0.01]; P = 0.0266). Baseline CVD history was predictive of CVD events during follow-up for SA (P < 0.0001) but not WE (P = 0.189). Mean age at death was 66.8 (11.8) for SA vs. 74.2 (12.1) for WE, a difference of 7.4 years (95% CI 1.0 to 13.7 years), P = 0.023. The adjusted odds ratio of CVD event or death from CVD was greater but not significantly so in SA than in WE (OR 1.4 [0.9 to 2.2]).

Limitations:

Fewer events in both groups and short period of follow-up are key limitations. Longer follow-up is required to see if the observed differences between the ethnic groups persist.

Conclusion:

South Asian patients with type 2 diabetes in the UK have a higher cardiovascular risk and present with cardiovascular events at a significantly younger age than white Europeans. Enhanced and ethnicity specific targets and effective treatments are needed if these inequalities are to be reduced.

Key words:

• Cardiovascular risk
• Diabetes
• Ethnicity

Transparency

Declaration of funding/role

The following companies and societies provided financial support in the form of grants for the UKAD Study: Pfizer, Sanofi-Aventis, Servier Laboratories UK, Merck Sharp & Dohme/Schering-Plough, Takeda UK, Roche, Merck Pharma, Daiichi-Sankyo UK, Boehringer Ingleheim, Eli Lilly, NovoNordisk, Bristol Myers Squibb, Solvay Health Care and Assurance Medical Society, UK. These companies did not contribute to the design of the study, in the collection, analysis, and interpretation of data; in the writing of the report; or in the decision to submit the paper for publication. Dr O'Hare and Professors Kumar and Barnett had the original idea for and designed the project. Mr N.T. Raymond contributed to study design and conducted/supervised statistical analysis. Dr S. Bellary and Miss S. Mughal were responsible for day to day running of the project, helping with data collection and analysis. All authors contributed to writing the paper and data interpretation.

Declaration of financial/other relationships

P.O.H., S.K. and A.H.B. have declared that they received research grants and honoraria for lectures and advisory work from the companies mentioned above who provided funding for the study. All other authors have declared no relevant financial relationships.

Peer reviewers may receive honoraria from CMRO for their review work. The peer reviewers have disclosed no relevant financial relationships.

Acknowledgements

We would like to acknowledge all the following members of the UKADS study group for their contributions to this study:

University of Birmingham and Heart of England NHS Foundation Trust, Birmingham, UK

S. Begum, T. Kauser, N. Mirza, A.N. Dixon, A. Rahim, W. Malik, R.A. Bhatti, M.M. Alvi, A. Akthar, R.A.S. Sangra, N.H. Bangash, M.D. Sheik, A.G. Hakeem, B.G. Najak, S.A. Latif, J.S. Sanghera, A.U. Shah, T. Sen-Gupta, G. O'Gara, P.S. Moonga, S.H. Khattak, P. Machin, F. Hartland, H. Kaur, N. Janood, J. Dhalival, T. Fatima, J. Taylor, D. Fitzpatrick, J. Lucas, S. Hemming.

Warwick Medical School, Warwick University and University Hospital Coventry and Warwickshire, Coventry, UK

A. Szczepura, K. Johal, A. Gumber, I.C. Agarwal, D.K. Mistry, F.F. Lyall, M.R. Dhadhania, K.L. Kakad, U. Jetty, J.F. Sihota, S. Mall, K. Webb, S. Khatoon, R. Parker, P. Claire, G. Turner.

On behalf of the UKAD Study Group.